Furnace seal



NOV- 12, 1963 H. M. ANDERSEN ETAL 3,110,484

FURNACE SEAL Filed Nov. 5. 1960 5 Sheets-Sheet 2 (D rf) INVENTORS. n HOWARD/VANDERSEN BYROBERT E. BUCKHOLDT ATTORNEY.

Nov. l2, 1963 H. M. ANDERSEN ETAL FURNACE SEAL 3 Sheets-Sheet 5 Filed Nov. 5. 1960 INVENTORS. HOWARDMANDERSEN BYROBERT E. BUCKHOLDT ATTORNEY.

United States Patent O 3,110,484 FURNACE SEAL Howard M. Andersen, Philadelphia, and Robert E. Buckholdt, Abington, Pa., assignors to Selas Corporation of America, Dresher, Pa., a corporation of Pennsylvania Filed Nov. 3, 1960, Ser. No. 67,052 4 Claims. (Cl. 263-40) The present invention relates to furnaces, and more particularly to a seal to be used between a stationary and a movable part of a furnace structure.

In most furnaces there are parts -that move relative to each other to give access to the interior of the furnace, and for other reasons. The space between these parts must be sealed to prevent inflow of air or outflow of furnace gases. A good seal is particularly necessary with some types of continuous strip annealing furnaces in which the furnace is moved from a position surrounding the strip to a position adjacent thereto.

-Itis an object of the invention to provide a seal between a movable and a s-tationary part of a furnace system.

It is a further, and more specific, object of the invention to provide a mechanically operated seal between the movable furnace portion and the stationary portion of a strip heating furnace structure.

In practicing the invention, the stationary portion of the furnace structure is provided with a heat resistant seal that can be moved from a retracted position away from the movable furnace unit into Ia. sealing position in which it engages a sealing flange on the movable furnace unit.

The various features of novelty which characterize our invention are pointed out with particul-arity in the claims annexed to `and forming -a part of this specication. For a better understanding of the invention, however, its advantages Iand specific objects attained with its use, reference shou-ld bev had to the accompanying drawings and descriptive matter in which we have illustrated Iand described a preferred embodiment of the invention.

IIn the drawings:

FIG. l is a perspective view diagrammatically showing the vfurnace structure,

FIG. 2 is a side view of -a portion of the furnace seal,

FIG. 3 is a section view taken on line 3-3 of FIG. 2,

FIG. 4 is a plan view of a corner of the seal, and

FIG. 5 is a View of a modified form of seal.

Referring to FIG. 1 of the drawing, there is shown a furnace structure including a furnace unit 1 which may be, and preferably is, of the type shown in Paten-t 2,869,864, which is used for heating continuously strip material for -annealing or other purposes. The furnace unit is mounted for lateral movement between lixed prtions including an upper duct section 2 and a lower guide section 3. It will be seen that the strip 4 passes vertically through the sections 1, 2 and 3, and is heated during its passage through furnace unit -1. The furnace, as described in more detail in the above mentioned patent, is U-shaped in section, and is provided with a slot in one edge thereof. In. normal operation of the furn-ace, this slot is closed by engagement of the edge of the furnace with a stationary abutment 6 that extends the length of the furnace unit. The furnace is provided adjacent to its upper end on each side with a pair of rollers 7 that -ride on tracks 18 extending transversely of the furnace. The furnace is in the position shown when it is heating the strip, but can be moved to the right in the drawing along the tracks 8 beyond the edge of the strip. When this is done, the strip will pass between the edges of slot 5, so that the furnace can be moved without disturbing the strip. The upper end of the furnace can be sealed by a conventional sand seal arrangement shown at 9. The lower end of the furnace, however, should be sealed with an arrangement which will give a more positive seal than is possible ywith a sand seal. The invention is concerned primarily with the details of this seal and its combination with the furnace structure.

Referring to FIGS. 2, 3 and 4 of the drawing, it will be seen that around the lower edge of the furnace there is provided an outwardly extending flange 12 against which va movable seal strip presses to close the space between the furnace unit and 4the station-ary guide section 3. The seal strip is comprised of a plurality of asbestos tapes that are placed on edge with alternate wide tapes 13 and narrow tapes 14. These tapes rest upon a ledge that is formed by one flange of an angle iron 15 which is welded to ya. vertically extending plate 16. The strips are held in position on the lflange 15 and are forced against plate I16 by =a squeeze plate 17 and bolts 18.

The plate 16 extends entirely around portion 3, and forms a sliding frame so that the parts attached thereto can slide vertically into and out of engagement with flange 12. The guiding means for the frame or plate 16 consists of an angle iron that is fastened to and projects beyond the edge of the lower guide section 3. This angle iron is provided with a horizontal flange 19 and a vertical ange 21, which is separated from frame 16 by la spacer 22. Each side of frame `16 is resiliently forced toward spacer 22 by `spring force. To this end bolts 23 extend through yflange 21 `and spacer 22 beyond frame 16. Each of these bolts has on it a pair of washers 24 against the inner surfaces of which the ends of -a compression spring 25 bear. The force of these springs, and therefore the force with which the sides of frame 16 are moved toward flange 21, can be adjusted by nuts 26 'which are received on bolts 23. A series of these bolts and the parts carried thereby extend at spaced distances along the flange 21 and around stationary portion 3. Vertical movement of frame 16 relative to spacer 22 is limited by me-ans of slots 27 formed in the frame, :and 'which surround the bolts 23. 'It is noted that Washers 24 are large enough to engage and push against the frame around the sides of the slot. -It is also noted that the vertical flange of angle iron 15 is provided with cut-out portions 28 around the washers 24, so .that these flanges will not interfere with vertical movement of the seal.

In order to prevent any leakage between frame 16, 'which carries the seal members 13 and spacer 22, there is provided a ywasher 29 of asbestos tape or the like, which rests on spacer 22 between the vertical leg 21 of the angle iron `'and the frame. This washer is held in position by a clamp 31 that is bolted to the horizontal leg 19 of the angle iron.

The frame 16 and the parts carried thereby are moved vertically into and out yof engagement with the llange 12 to seal the space between the furnace unit 1 and the stationary portion 3. This is accomplished by having frame 16 moved vertically through hydraulic or pneumatic pressure that is applied at opposite ends of cylinders 33 attached by brackets 34 to the stationary portion 3. Each of these cylinders receives a piston -that is attached to the end of a piston rod 35'. The piston rods are connected by links 36 with the ange 15. To this end the upper end of each lin-k 36 receives a pivot pin 37 that extends through a yoke 38 formed by lugs that are welded to flange 15.

In the operation of the apparatus, when strip is being heated, the furnace unit 1 is in the posi-tion shown in FIG. 1 between the stationary duct portion 2 and lower portion 3 of the furnace structure. At this time, iluid pressure is applied to the lower end `of the cylinders 33 to move the seal 13 tightly into engagement with the bottom surface of flange 12. Thus the space between the furnace unit 1 and the structure 3 is sealed against the inflow of air into the furnace. The tapes 1.3 are sufficiently resilient to take care of any slight irregularities in Ithe lower surface of iiange 12. The continuous washer 219' will prevent leakage past the frame 16. When the furnace is to be retracted to the rig-ht in FIG. l, in order to stop heating of the strip, fluid pressure is applied to the upper ends of the cylinders 33 to move frame 16 and the sealing strips downwardly away from iiange .12. The furnace can Ithen be moved to its retracted position. it will be seen from PIG. 3 of the drawing that the space between ange 12 and flange 19 is slightly below the parting line between the center portion of the furnace and the top of portion 3 of the f-urnace struct-ure. In order to prevent radiation from the furnace from injuring the metal portions of the seal, there is provided a refractory block 39 which is horizontally aligned with the parting line. It will therefore be seen that all metal parts of the seal are protected from direct radiation of the hottest portion of the furnace, so that these parts will not be affected adversely by radiation.

In FIG. there is shown another form that the furnace seal can take. In this figure, the lower end of the furnace unit Il has running around its edge a Water jacket formed by an outwardly extending ange 41 and a channel 42. There is also provided a water jacket 43 around the edge of stationary portion 3 of the furnace. This latter water jacket has a ange 44% extending outwardly from it, which flange does not project outwardly as far as the lower surface of channel '42.` The seal extends between anges 42 and 44 and includes a pair of asbestos ropes 45 and 46 extending around portion 3, that engage respectively the lower surfaces of these flanges. Rope 45 is held in a backing member 47, while rope 46 is held in a backing member 4S. These two members are welded along their length to a plate 49, so that the ropes and the plate form a unit. The plate 49 is pivoted at spaced points 51 to supports 52 that are located at spaced points around furnace portion 3. The supports are raised and lowered to move the seal ropes to engagement with their respective anges by means of a series of rods 53 forming part of diaphragm motors 54 that are mounted on portion 3` by brackets 55. The motors are of the type which are biased by weight of the pants carried by rods 53 in `a downwardly direction to open the seal. The application of pressure through pipes 56 to the lower surface of the diaphragm chambers 54 will move the rods `53 upwardly to close the seal.

In this embodiment of the invention, as in the previous one, it -is intended that the anges 42 and -44 extend entirely around the periphery ofthe furnace. The ropes 45 and 46 also extend `around the furnace, so that when the seal is to be closed, the application of 'air to the diaphragm motor will move the ropes into engagement with the flanges `42 and 44. In view of the fact that plate 49 carrying the seals is pivoted to its supports, this plate can rock slightly to insure that Ia good seal will be obtained even though there may be slight relative movement between the furnace and stationary portion 3 due to expansion of the furnace as its temperature is changed.

-From the above, it will be seen that we have provided a furnace seal which can be used between a stationary and a movable portion of a furnace structure, and one that can be readily opened when it is desired to move the movable portion of the furnace. Since the sealing elements are made of a material that is slightly resilient, the application of pressure to the seal supporting members will close the space between the movable and stationary portions of the furnace structure tightly, even though these portions may shift a small amount relative to each other.

While the above [description shows that the seal itself is carried by a stationary portion of the furnace structure, and this is the desirable arrangement, it will be obvious that the seal could be on the movable portion of the furnace if it twas desired. In either case, the operation and the sea-ling would be -the same.

While in accordance with the provisions of the statutes, we have illustrated and described the best form of embodiment of our invention now known lto us, it will be lapparent to those skilled in the art that changes may be made in the form of lthe apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features :of our invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. In a furnace structure, a furnace having an opening therein and a first flange extending outwardly from said furnace substantially perpendicularly to said opening, struc-ture spaced from said furnace and disposed in front of said opening, and means to seal the space between said furnace and structure around said opening comprising a second flange surrounding said structure, la frame substantially the same size as said tirst flange surrounding and slidable on and guided by said second ange, sealing means between said second ange and frame, means to force said frame toward said second flange tocompress said sealing means, a sealing strip attached to said frame and extending toward said rst ange, and means tov move said frame toward and from said first ange to move said sealing strip into engagement with said tirs-t ange and thereby seal the space between said furnace` and structure.

2. In combina-tion, a furnace having an opening therein, a iiange on said furnace around said opening and extendsubstantially perpendicularly thereto, structure located in front of said `opening and spaced from said furnace, means on said structure having a guiding surface aligned with said ange and perpendicular thereto, a frame surrounding and slidable on and guided by said surface, sealing means operative to prevent gas leakage between said fname and surface, means to force said frame toward said surface -against said sealing means, a sealing strip on said frame tand projecting toward said ange, means to hold said sealing strip rigidly on said frame, land means toI slide said frame in opposite directions on said surface to bring said sealing strip into and out of engagement with said ange.

3. The combination of claim 2 including means to mount one of said furnace land structure for movement ylaterally of the other.

'4. The combination of claim 2 including cooperating means on said furnace and structure to shield said sealing strip from direct radiation from said furnace.

References Cited in the file of this patent UNITED STATES PATENTS (Addition to No. 1,060,618) 

2. IN COMBINATION, A FURNACE HAVING AN OPENING THEREIN, A FLANGE ON SAID FURNACE AROUND SAID OPENING AND EXTENDSUBSTANTIALLY PERPENDICULARLY THERETO, STRUCTURE LOCATED IN FRONT OF SAID OPENING AND SPACED FROM SAID FURNACE, MEANS ON SAID STRUCTURE HAVING A GUIDING SURFACE ALIGNED WITH SAID FLANGE AND PERPENDICULAR THERETO, A FRAME SURROUNDING AND SLIDABLE ON AND GUIDED BY SAID SURFACE, SEALING MEANS OPERATIVE TO PREVENT GAS LEAKAGE BETWEEN SAID FRAME AND SURFACE, MEANS TO FORCE SAID FRAME TOWARD SAID SURFACE AGAINST SAID SEALING MEANS, A SEALING STRIP ON SAID FRAME AND PROJECTING TOWARD SAID FLANGE, MEANS TO HOLD 